Fisheries Ecology Research Articles

Initial Alterations of Fish Community Structure and Diversity Following Fishing Cessation in Qilu Lake, China.

The Qilu Lake is an eutrophic shallow lake located in Yunnan Province, China. An ecological fishery project was initiated in the lake from 2011 to 2021 to introduce filter-feeding fish species that feed on algae, with the aim of improving water quality. In January 2022, when the ecological fishery project expired, all fisheries-related activities (including fish stocking and fishing activities) ceased in the lake. To comprehensively evaluate the initial alterations in fish community structure and diversity resulting from the fishing cessation in the Qilu Lake, the present study conducted field surveys within the one year before the fishing cessation (referred to as BFC) and the one year after the fishing cessation (referred to as AFC). A total of twenty-one fish species were collected, including four native species. Four species were recorded in the lake for the first time, including Pelteobagrus fulvidraco, Pelteobagrus vachelli, Paramisgurnus dabryanus, and Hyporhamphus intermedius. The number of fish species decreased from 21 to 13 following the fishing cessation. The fishes collected in both BFC and AFC are mainly omnivorous-feeding and of bottom-dwelling habits. The mean size of the fishes in the AFC sample shows a significant decrease compared to those in BFC. After the fishing cessation, the Shannon-Wiener diversity index and Margalef richness index of the fish slightly declined. The fish community structure of the Qilu Lake exhibits a high degree of similarity to adjacent lakes in central Yunnan. Our study demonstrates a significant shift in the fish community of the Qilu Lake following the fishing cessation, one which may adversely impact the stability of the lake ecosystem. To enhance fish species diversity in the Qilu Lake, it is recommended that policies be implemented to promote the ecological fishery project and improve habitat restoration for native fish species, while also regulating fish community structure.

Evaluation of the efficacy of implementing Ecosystem-Based Management (EBM) strategies within fisheries across the middle and lower Yangtze River basin lakes in China

To mitigate the decline of fishery resources and the exacerbation of water pollution in Chinese lakes and to enhance the potential and sustainable use of lake fisheries, the Chinese government has actively implemented principles and models of ecosystem-based lake fishery management. This includes promoting ecological aquaculture techniques and the “retiring pens to restore lakes” policy. To assess the effects of ecosystem-based management on Chinese lake fisheries, data from 2007 to 2020 were collected for the Qiandao Lake, Tai Lake, Hongze Lake, Luoma Lake, and Gaobao Lake in the middle and lower reaches of the Yangtze River. The study employed Data Envelopment Analysis (DEA) to assess fishing efficiency through a static input-output efficiency model. Additionally, the Malmquist index and distance functions were used for a dynamic comparison of total factor productivity (TFP) across the five lake management models. The results indicate that trends in technological progress, scale efficiency, and TFP were consistent across the lakes from 2013 to 2020. Qiandao Lake, Tai Lake, and Hongze Lake showed a positive average annual growth rate in TFP, with Qiandao Lake having the highest average annual growth rate of 13.2%. In contrast, Gaobao and Luoma Lakes experienced a negative growth rate in TFP. Furthermore, Qiandao Lake exhibited significantly higher technical efficiency than the other four lakes, effectively achieving an efficient state, followed by Hongze Lake. The study demonstrates that technological progress and variations in scale efficiency are the primary factors driving the increase in TFP in fisheries. Promoting ecosystem-based “fishing for water conservation” aquaculture techniques and restricting aquaculture scale through the “retiring pens to restore lakes” policy contribute to enhancing TFP in ecological fisheries.

Measurement of Ecological Fisheries Efficiency in Selected Coastal Cities Based on the NDDF Model

Measurement of Ecological Fisheries Efficiency in Selected Coastal Cities Based on the NDDF Model

Xenobiotics and pollution of Lake Ladoga

Advances in applied chemistry have led to the emergence of a new group of organic toxicants - xenobiotics, which have found wide application in industry, agriculture and everyday life, and quickly spread through the biosphere, exerting a prolonged effect on living organisms, including humans. Research was carried out in the waters of the Shlisselburg, Volkhov and Svirskaya lips of the littoral zone of the southern part of Lake Ladoga in the period 2020-2023, using generally accepted methods of biological and chemical analytical analysis of fish and their habitat. 1500 specimens were examined. Fish and 3000 larvae. Chemical-analytical studies of samples of water, bottom sediments, atmospheric precipitation and fish for metals were carried out in the laboratory of fishery ecology of the St. Petersburg branch of the Federal State Budgetary Institution "VNIRO" ("GosNIORH" named after L.S. Berg) on an atomic absorption spectrophotometer AA - 7000 (Shimadzu) according to approved methods (PNDF., 2010; M02-2406., 2013 and M02-902-125, 2005), and in the research laboratory of food and natural objects "ANALECT" of the Institute of the Ministry of Health of the Russian Federation, using the method of atomic absorption spectrometry according to approved methods. Hydrochemical and hydrological indicators were determined using an automatic multiparameter probe Aqua TROLL 500. The content of metals in the fish habitat at the surveyed equators, as dangerous toxicants and previously significant for Lake Ladoga, showed their low content and especially such highly toxic ones as lead and cadmium. Minor excesses were noted for copper and manganese, but they could not in themselves be the cause of pathological manifestations of toxicosis in fish and disruption of the process of their natural reproduction.

The historical ecology of subsistence and early commercial fisheries in mangrove systems in Brazil

The historical ecology of subsistence and early commercial fisheries in mangrove systems in Brazil

Good practices for surplus production models

Surplus production models (SPMs) have a long history in fisheries ecology and are important for the assessment and management of marine species and stocks. However, the implementation, application, and usage of these models vary across regions and case studies. Good practice guidelines can streamline modelling workflows, inform the acceptance or rejection of an assessment, and facilitate the derivation of management advice from accepted assessments. This paper discusses current practices in the application of SPMs and proposes good practice guidelines for their use in stock assessment. We complement our recommendations with results from a simulation study examining the performance of an age-based operating model and a SPM assessment model under 60 scenarios with various assumptions regarding data quantity, quality, and model priors. We provide specific good practice guidelines for two widely used state-space SPMs: SPiCT and JABBA. Finally, we discuss current limitations and suggest avenues for future developments for SPMs.

Spatial information extraction of fishing grounds for light purse seine vessels in the Northwest Pacific Ocean based on AIS data

Ecological fishery management requires high-precision fishery information to support resource management and marine spatial planning. In this paper, the Automatic Identification System (AIS) was adopted to extract the spatial information on the fishing grounds of light purse seine vessels in the Northwest Pacific Ocean. The spatial distributions of fishing grounds mapped by the data mining, kernel density analysis and hotspot analysis methods were compared. The spatial similarity index was applied to determine the spatial consistency between the computed spatial information and fisheries resource information. Finally, the spatial information derived by the best method was used to investigate the characteristics of fishing activity. The results showed that: the speed of light purse seine vessels related to operations was lower than 1.6 knots. The spatial information extracted by the three methods was consistent with the catch data distribution, and the spatial similarity between the fishing effort and catch data was the highest. The spatial variation in fishing activity was similar to that in the chub mackerel migration route. AIS data could be used to provide high-resolution fishery information. Light purse seine fishing vessels typically operate and travel along the exclusive economic zone boundary, and increased attention must be given to fishing vessel operation supervision. A comprehensive supervision system can be employed to monitor the operations of fishing vessels more effectively. The results of this study can provide technical support for the management of fishing activities and conservation of marine resources in this region using AIS data.

A thoughtful guide to fisheries ecology and conservation for the next generation

A thoughtful guide to fisheries ecology and conservation for the next generation

Impact of exposure temperature rise on mass mortality of tidal flat pacific oysters

Oysters are a major commercial and ecological fishery resource. Recently, the oyster industry has experienced mass mortality in summer due to environmental factors. Generally, the survival of oysters in aquatic environments is mainly impacted by environmental stressors such as elevated sea temperatures and reduced salinity; however, the stressors impacting tidal flat oysters that are repeatedly exposed to air remain poorly understood. Hence, we studied the relationship between environmental factors and the survival of tidal flat pacific oysters in Incheon, South Korea, where mass mortality is common. Principal component analysis and Bayesian networks revealed that air temperature (in spring and summer) and sea temperature (in summer) are related to oyster production. In habitats of the tidal flat oysters during the summer, high temperatures of 34.7–35.4°C (maximum 47.6°C) were observed for average durations of 0.8–1.9 hours (maximum 3.6 hours). Furthermore, heat waves occurred for up to 12 consecutive days. Results from the multiple stress test showed that when exposed to 45°C (air temperature) for 4 hours per day, the survival rate of oysters was 42.5% after only 2 days and 0% after 6 days. The findings stemming from the field observations and stress tests suggest that high temperatures during emersion may contribute to mass mortality of oysters in summer, indicating a potential threat to oysters due to climate change. To understand the effects of future thermal stress on oysters more accurately, simultaneous long-term trend analyses and field-based observations are required.

Remaking the Future Studies of Global Small-Scale Fisheries; Bibliometric Analysis Findings Between 1965 and 2020

Small-scale fisheries (SSF) have long been recognized as critical to many facets of human life. SSF-related bibliometric studies have focused on specific topics, including marine protected areas and sustainable utilization. Since SSF is associated with numerous dimensions of life, a comprehensive bibliometric study is required. This study aims to analyze and visualize state of the art in SSF research using bibliometric analysis on articles published between 1965 and 2020 obtained from the Scopus database in August 2021. Harzing's Publish or Perish, VOSviewer, and Microsoft Excel software were used to fulfill the objectives. The findings indicate that SSF research, more prevalent in the areas of Agricultural and Biological Sciences, grew slowly from 1965 to 1997 before increasing. Initially, the publication themes were bio-ecological before associated with management concerns and evolving into a more socio-economic tone. With an average of 35.75 citations per year, Allison and Ellis's 2001’s article was the most cited paper. In terms of total publication, Brazil and The University of British Columbia were the most productive countries and affiliations (210 and 42 articles, respectively). SFF's future research should prioritize local fisheries ecology and resources assessment, as well as addressing cross-disciplinary issues such as socio-ecological system resilience. Collaborations between authors from different countries and institutions are also more expected.

Comparing diversity patterns and processes of microbial community assembly in water column and sediment in Lake Wuchang, China.

The study compare the diversity patterns and processes of microbial community assembly in the water and sediment of Lake Wuchang (China) using high-throughput sequencing of 16S rRNA gene amplicons. A higher microbial α-diversity in the sediment was revealed (P < 0.01), and the most common bacterial phyla in water column were Proteobacteria, Cyanobacteria and Actinobacteria, while Proteobacteria, Acidobacteria, Chloroflexi and Nitrospirae were dominant in sediment. Functions related to phototrophy and nitrogen metabolism primarily occurred in the water column and sediment, respectively. The microbial communities in water column from different seasons were divided into three groups, while no such dispersion in sediment based on PCoA and ANOSIM. According to Pearson correlation analysis, water temperature, dissolved oxygen, water depth, total nitrogen, ammonium, and nitrite were key factors in determining microbial community structure in water column, while TN in sediment, conductivity, and organic matter were key factors in sediment. However, the stochastic processes (|βNTI| < 2) dominated community assembly in both the water column and sediment of Lake Wuchang. These data will provide a foundation for microbial development and utilization in lake water column and sediment under the circumstances of increasing tendency of lake ecological fishery in China.

Development of Potential Indicators of Aquaponics Industry

Aquaponics is a sustainable method of farming fish and vegetables, so it is highly valued by individuals, entrepreneurs, educators, and governments. It is a special aquacultural method that creates economic and ecological benefits. Considering that the development of the aquaponics industry is leading the ecological fishery industry in the future, a set of indicators to evaluate the potential of the aquaponics industry is necessary to be developed. Therefore, a literature review and the Delphi method were used to establish a set of indicators for the investigation of the development of the aquaponics industry. As a result, the key implementation strategies were proposed from five aspects: environmental conditions, resource conditions, industrial conditions, technical conditions, and policy conditions of aquaponics. In the central trend analysis, 48 potential indicators of the aquaponics industry were defined. Important indicators were found in the environmental and resource conditions, followed by industrial and technological conditions, and policy conditions in the order of the number of indicators. The most important indicators were “water quality control: complete technical knowledge of water temperature control or operation of dissolved oxygen nutrients” and “water pollution control: have generated water pollution control or operation technical knowledge”. For future strategies, we suggested the following implementation strategies: (1) taking the aquaponics industry as the important object of rural revitalization policies, (2) taking various indicators as the basis of policy implementation, and (3) establishing the promotion group of aquaponics.

Insights into the bacterial community compositions of peanut worm (Sipunculus nudus) and their association with the surrounding environment

The peanut worm (Sipunculus nudus) is an important economic and ecological fishery resource in China. To determine how S. nudus interacts with its culture environment, in this study, the diversity, composition, and interrelationships of bacterial communities in the intestine, coelomic fluid, and culture environment of S. nudus through high-throughput sequencing using the Illumina HiSeq sequencing platform. Alpha diversity analysis showed that the highest bacterial community richness and diversity were found in the sediments. Species annotation revealed that Proteobacteria dominated in all samples (48.92%–58.36%), and the other dominant phyla were highly variable, indicating a certain independence between the environment and the composition of the bacterial community of S. nudus. The coelomic fluid of S. nudus contained high concentrations of Bacillus and could be a source of potential probiotic bacteria for isolation and culture. Cluster and operational taxonomic unit Venn diagram analyses showed that the bacterial community composition in the intestine was more similar to that in the sediments compared with water. The predicted functional analysis of bacterial communities indicated that the functions of bacterial communities in the different surrounding environment were highly similar and involved in various aspects, such as membrane transport, amino acid metabolism, carbohydrate metabolism, and replication and repair. Our findings have important implications on the establishment of sustainable microecological regulation and management strategies for S. nudus culture and provide a reference for the development and utilization of probiotic bacteria.

From spawner habitat selection to stock-recruitment: Implications for assessment.

The relationship between the spawning stock size and subsequent number of recruits is a central concept in fisheries ecology. The influence of habitat selection of spawning individuals on the stock-recruitment relationship is poorly known. Here we explore how each of four different spawner behaviors might influence the stock-recruitment relationship and estimates of its parameters in the two most commonly used stock-recruitment functions (Beverton-Holt and Ricker). Using simulated stock-recruitment data generated by four different spawner behaviors applied to multiple discrete habitats, we show that when spawners were distributed proportionally to local carrying capacities, there was small or no bias in estimated recruitment and stock-recruitment parameters. For an ideal free distribution of spawners, larger bias in the estimates of recruitment and stock-recruitment parameters was obtained, whereas a random and a stepwise spawner behavior introduced the largest bias. Using stock-recruitment data corresponding to a "realistic" range of population densities and adding measurement error (20%-60%) to the simulated stock-recruitment data generated larger variation in the estimation bias than what was introduced by the spawner behavior. Thus, for exploited stocks at low population density and where spawning stock size and recruitment cannot be observed perfectly, partial observation of the possible spawner abundance range and measurement error might be of higher concern for management.

Evaluation of Marine pasture fishery production based on big data in the context of low-carbon economy

Modern Marine ranching is a new sustainable production mode of Marine fishery, which plays an important role in the transformation and upgrading of Marine fishery in China. However, the Marine ecological environment is increasingly damaged, Marine living resources, especially economic species, the scope of offshore and traditional fishing grounds is constantly reduced, and the quality of aquaculture degradation, which are reflected in different degrees in both fishery developed countries and fishery developing countries, and eventually lead to a series of social and economic problems. And with the development of modern information technology, oceanic ranch produced all kinds of big data is growing fast at the speed of visible to the naked eye, cause for storage of data cannot be timely and effective, without all the data storage, data is not found in time, the relationship between the and the stored data is not fully development and utilization of their potential value. Therefore, this paper sorted out the construction status and existing problems of modern Marine ranches in China, and put forward corresponding construction plans for the development of Marine ranches in China from the perspective of the government, so as to make up for the deficiencies in the evaluation and research of Marine ranches in China at the present stage and provide theoretical guidance for the construction of Marine ecological fisheries.

Feeding Ecology of Common Squid Todarodes pacificus in the South Sea of Korea Determined through Stable Isotope and Stomach Content Analyses

The common squid Todarodes pacificus is a dominant species within epipelagic communities and an important commercial species in the South and East seas of Korea and in the East China Sea. In this study, to examine the dietary composition, trophic position, and ontogenetic dietary shifts of the common squid, we analyzed stomach contents and stable isotope values (δ13C and δ15N) in muscle tissue across different body sizes (mantle length, ML) and seasons (winter, spring, and summer 2021) in the South Sea of Korea. Regardless of the season, the diet of the common squid predominantly comprised Pisces (37.9–94.0%) and Cephalopoda (6.0–61.0%). However, in the smallest individuals (ML &lt; 10 cm), the stomach contents in August primarily comprised Crustacea (95.5%), thereby indicating a seasonal difference in dietary composition and ontogenetic dietary shifts only during summer. Similarly, our isotope results revealed seasonal isotopic variation among sampling periods and significant positive correlations between ML and both δ13C and δ15N values during the summer. These results reveal a seasonal variability in major diet components among the common squid of different size classes and that their feeding strategies are probably adjusted in response to the temporal availability of prey. Collectively, the findings of this study enhance our understanding of the feeding ecology of T. pacificus and thereby provide valuable information that will contribute to the ecological fishery management of this commercially important species.

DEPD model for evaluating marine ranching ecological security and its application in Shandong, China

As an ecological fishery enhancement mode, marine ranching can conserve fishery resources and restore degraded marine environments. However, research on marine ranching ecological security (MRES) is nascent, and the few studies evaluating MRES are relatively subjective. To fill this gap and objectively evaluate MRES, this study constructed a model (abbreviated DEPD) that combined four methods: driver-pressure-state-impact-response (DPSIR), entropy weight method (EWM), path analysis (PA), and decision-making trial and evaluation laboratory (DEMATEL). DPSIR was used to construct an evaluation index system and provide the possible influence relationships of MRES. EWM was used to determine the index weight in each DPSIR element while PA examined the possible influence relationships and determined the effective influence mechanism. DEMATEL was used to determine the weights of five elements considering the direct and indirect effects between them in the DPSIR framework. The established DEPD model was then applied to 20 marine ranching enterprises in Shandong, China. The results showed that 20% of the enterprises were at the level of “most secure,” 10% “relatively secure,” and 70% “least secure.” Although the MRES of national enterprises is better than that of provincial ones, the overall performance is low and needs improvement.

Fishing regulations, sexual dimorphism, and the life history of harvest

Freshwater recreational fisheries regulations are a vital tool for achieving social and ecological fisheries objectives. However, angler behavior and fish biology may interact to influence regulation efficacy in unexpected ways. We combined models of fish growth and angler behavior to explore how angler behavior interacts with fish life history to shape the probability of fish harvest given capture across ages, life stages, and sexes of walleye ( Sander vitreus). Compared to females, males grew more quickly as juveniles, matured earlier, and reached smaller maximum sizes. Male walleye were therefore vulnerable to harvest for more of their reproductive lives than females because males spent more time at sizes where anglers were very likely to harvest them. We suggest that restricting harvest of large individuals in sexually dimorphic species may favor the survival of large, reproductive-aged females. Moreover, we show that combining models of fish growth and harvester behavior can provide insights into how harvest affects fish with complex life histories over the course of their lives.

Combining scientific survey and commercial catch data to map fish distribution

AbstractDeveloping Species Distribution Models (SDM) for marine exploited species is a major challenge in fisheries ecology. Classical modelling approaches typically rely on fish research survey data. They benefit from a standardized sampling design and a controlled catchability, but they usually occur once or twice a year and they may sample a relatively small number of spatial locations. Spatial monitoring of commercial data (based on logbooks crossed with Vessel Monitoring Systems) can provide an additional extensive data source to inform fish spatial distribution. We propose a spatial hierarchical framework integrating both data sources while accounting for preferential sampling (PS) of commercial data. From simulations, we demonstrate that PS should be accounted for in estimation when PS is actually strong. When commercial data far exceed scientific data, the later bring little information to spatial predictions in the areas sampled by commercial data, but bring information in areas with low fishing intensity and provide a validation dataset to assess the integrated model consistency. We applied the framework to three demersal species (hake, sole, and squids) in the Bay of Biscay that emphasize contrasted PS intensity and we demonstrate that the framework can account for several fleets with varying catchabilities and PS behaviours.

Critical factor identification of marine ranching ecological security with hierarchical DEMATEL

Marine ranching as an ecological fishery proliferation mode has attracted the attention of various countries after its emergence and has become a hotspot for marine economic development. The marine ranching ecological security (MRES) refers to a healthy state where the system, in which the resources and environment are stable and sustainable, can realize its functions properly and has a certain resilience to external threats. MRES is the basis for achieving the economic and social benefits of marine ranching, but there are few studies concern about assessing it currently. Therefore, this study combines the driver-pressure-state-impact-response (DPSIR) model, the technology-environment-resources-economy (TERE) model, and the hierarchical DEMATEL method to identify the critical factors for the MRES system. Finally, according to the relations among critical factors, this study makes recommendations for improvements with specific measures based on the advanced experience and the development status of marine ranching in China. Effective critical factors identification of MRES will help point out the direction for improving ecological security, and promote the sustainable development of marine ranching.